Kinetics of muscle deoxygenation and microvascular PO2 during contractions in rat: comparison of optical spectroscopy and phosphorescence-quenching techniques
Kinetics of muscle deoxygenation and microvascular PO2 during contractions in rat: comparison of optical spectroscopy and phosphorescence-quenching techniques
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DOI：
10.1152/japplphysiol.00925.2011
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发表时间：
2012-01-01
影响因子：
3.3
通讯作者：
Poole, David C.
中科院分区：
文献类型：
--
作者：
Koga, Shunsaku;Kano, Yutaka;Poole, David C.
古贺S，卡诺Y，巴斯托TJ，费雷拉LF，大前E，须藤M，普尔DC.大鼠肌肉收缩过程中的脱氧和微血管PO 2动力学：光谱学和磷光猝灭技术的比较。J Appl Physiol 112：26-32，2012.首次发表于2011年10月6日; doi：10.1152/japplphysiol.00925.2011。用近红外光谱测量肌肉脱氧的总体假设是，信号主要反映肌内微循环区室，而不是肌细胞内肌红蛋白（Mb）。为了检验这一假设，我们比较了使用可见光光谱（适用于表面纤维层）的肌肉脱氧的动力学曲线与微血管O-2分压的动力学曲线（即，PmvO（2），磷光淬灭）在相同的肌肉区域（0.5类似于1 mm深度）内的雄性Wistar大鼠（n = 14）的腓肠肌中从休息到电刺激收缩的过渡期间。这两种反应都可以通过时间延迟（TD）建模，然后以接近指数的方式变化到新的稳定水平。然而，与磷酸化猝灭PmvO（2）相比，肌肉脱氧曲线的TD显著更长[脱氧和PmvO（2）分别为8.6 +/- 1.4和2.7 +/- 0.6 s（平均值+/- SE）; P < 0.05]。反应的时间常数（tau）没有差异（脱氧和PmvO（2）分别为8.8 +/- 4.7和11.2 +/- 1.8 s）。这些不同的（TD）反应表明，Mb的脱氧特性延长了TD，从而增加了肌肉脱氧开始前的持续时间（收缩次数）。然而，这种影响不足以增加平均响应时间。有些不同的是，在更深的区域使用近红外光谱测量肌肉脱氧反应，（类似于5 mm深度）（类似于50% I型富Mb，高氧化纤维）（τ = 42.3 ± 6.6 s; P < 0.05）比使用可见光光谱或PmvO（2）测量的浅表肌肉的相应值高并且可以根据PmvO（2）动力学中已知的纤维类型差异来解释。这些数据表明，在浅表和更深的肌肉区域内，脱氧信号的tau可以代表运动瞬变期间局部O-2提取动力学的有用指数。
Koga S, Kano Y, Barstow TJ, Ferreira LF, Ohmae E, Sudo M, Poole DC. Kinetics of muscle deoxygenation and microvascular PO2 during contractions in rat: comparison of optical spectroscopy and phosphorescence-quenching techniques. J Appl Physiol 112: 26-32, 2012. First published October 6, 2011; doi:10.1152/japplphysiol.00925.2011.-The overarching presumption with near-infrared spectroscopy measurement of muscle deoxygenation is that the signal reflects predominantly the intramuscular microcirculatory compartment rather than intramyocyte myoglobin (Mb). To test this hypothesis, we compared the kinetics profile of muscle deoxygenation using visible light spectroscopy (suitable for the superficial fiber layers) with that for microvascular O-2 partial pressure (i.e., PmvO(2), phosphorescence quenching) within the same muscle region (0.5 similar to 1 mm depth) during transitions from rest to electrically stimulated contractions in the gastrocnemius of male Wistar rats (n = 14). Both responses could be modeled by a time delay (TD), followed by a close-to-exponential change to the new steady level. However, the TD for the muscle deoxygenation profile was significantly longer compared with that for the phosphorescencequenching PmvO(2) [8.6 +/- 1.4 and 2.7 +/- 0.6 s (means +/- SE) for the deoxygenation and PmvO(2), respectively; P < 0.05]. The time constants (tau) of the responses were not different (8.8 +/- 4.7 and 11.2 +/- 1.8 s for the deoxygenation and PmvO(2), respectively). These disparate (TD) responses suggest that the deoxygenation characteristics of Mb extend the TD, thereby increasing the duration (number of contractions) before the onset of muscle deoxygenation. However, this effect was insufficient to increase the mean response time. Somewhat differently, the muscle deoxygenation response measured using near-infrared spectroscopy in the deeper regions (similar to 5 mm depth) (similar to 50% type I Mb-rich, highly oxidative fibers) was slower (tau = 42.3 +/- 6.6 s; P < 0.05) than the corresponding value for superficial muscle measured using visible light spectroscopy or PmvO(2) and can be explained on the basis of known fiber-type differences in PmvO(2) kinetics. These data suggest that, within the superficial and also deeper muscle regions, the tau of the deoxygenation signal may represent a useful index of local O-2 extraction kinetics during exercise transients.